The present invention relates to a device for applying coating composition to two sides of a moving web of material.
Such a device is known from Federal Republic of Germany Published Application OS 34 17 487, which corresponds to U.S. Pat. No. 4,848,268. FIG. 1 thereof shows two press rolls which are horizontally opposite each other. Within the press nip formed between them, the rolls transfer the coating composition, which had been applied onto their outer surface(s), to a web of material. The coating applicator mechanism employed in each case is a device which carries an elastic doctor holder, including a revolving doctor having circumferential grooves that serve as the doctor element. This device enables application of very small amounts of coating with coating compositions having very low solids content. The amounts of coating composition applied can have a solids content of from 2 to 3 g/m.sup.2 per side of the web of material. FIG. 3 of the patent shows a coating application arrangement using only one roll. A first coating applicator mechanism is associated at one side with the outer surface of the roll. On the other side, also in the region of the outer surface of the roll, there is a second coating applicator mechanism. It is provided with a nozzle chamber for applying coating composition directly onto the one side of the web of material. The other side of the web of material is coated from the outer surface of the roll. In FIG. 1 of that patent, the applicator mechanisms are each provided in the upper, outer quadrant (i.e., on the side of each roll facing away from in each case the other side) and are developed identically.